latigid aikon Posted June 14 Share Posted June 14 1 hour ago, MindSoup said: If anyone can suggest a practical and accurate way to measure LSTs then I'm all ears. Thermocouples seem like the obvious method. A quick google found people measuring leaf surface temps directly with thermocouples. https://climexhandbook.w.uib.no/2019/11/03/leaf-temperature/ Quote 5.5.1 What and how to measure? Most investigators are interested in measuring the leaf operating temperature, which is the temperature at which leaf physiological processes occur. Leaf operating temperatures can be determined through direct or indirect methods. Direct methods require either contact with the leaf (thermocouples), or are achieved remotely via non-contact thermal sensors (infrared thermometers or cameras). In either case, direct methods involve in situ measurement of leaves on intact live plants. The main indirect method involves measurement of stable isotopes of oxygen (δ18O) in plant tissue. This indirect method requires destructive sampling of plant tissues that are later processed and measured in the laboratory. Thermocouples consist of a soldered bead connecting two wires that are each composed of a different metal alloy. As a result of the thermoelectric effect, the thermocouple bead will produce a voltage that is a nonlinear function of temperature. Calibration relationships allow conversion between thermocouple bead temperature and measured voltages. Thermocouples attached to an in situ leaf will thus measure the leaf temperature after a period of equilibration (e.g. Hall et al., 2014). Link to comment Share on other sites More sharing options...
MindSoup Posted June 14 Share Posted June 14 (edited) But if a thermocouple is attached to the leaf it will it not effect the temperature of the leaf? And as the article says, " leaf temperatures can vary widely between environments, but also between plants growing under the same conditions and even within the canopy of a single plant" that would mean needing multiple couples across each plant and then make an average of the readings? That doesn't sound very practical to me. Edited June 14 by MindSoup Link to comment Share on other sites More sharing options...
latigid aikon Posted June 14 Share Posted June 14 1 minute ago, MindSoup said: But if a thermocouple is attached to the leaf it will it not effect the temperature of the leaf? It's worth reading some more of the document I posted, they cover that there. It's also interesting that they describe IR thermometers as "the bronze standard" but then go on to describe IR cameras as "the gold standard". 3 minutes ago, MindSoup said: That doesn't sound very practical to me. It's not going to get any more practical with any other method due to the reasons you describe I'm also not convinced that it's sensible to adjust the environment as a whole based on individual leaf readings unless you're measuring a large number simultaneously and even then; 20 hours ago, Military Grade said: Someone recently explained how most us misinterpreted what VPD is, it's a by product rather than a target to aim for or something along them lines , hopefully they see this thread and can explain it over again. I think that was @GSZZ and it made a lot of sense to me. Link to comment Share on other sites More sharing options...
MindSoup Posted June 14 Share Posted June 14 (edited) 17 minutes ago, latigid aikon said: It's worth reading some more of the document I posted, they cover that there. "Equilibration" cool word. Surprises me the micropore tape doesn't throw the readings off, still sounds like a whole load of fuckery. IR camera is probably the most practical but as you say who even cares, all you really have to understand is that humidity and temperature (as well as all other environmental parameters) have a relationship and to act accordingly on that knowledge. Precise measurement is not just impractical but more or less unnecessary unless you're an actual scientist. Edited June 14 by MindSoup 1 Link to comment Share on other sites More sharing options...
Military Grade Posted June 14 Share Posted June 14 Very Pointless Disappointment Sorry bored 1 1 Link to comment Share on other sites More sharing options...
The Green Manalishi Posted June 14 Share Posted June 14 5 hours ago, MindSoup said: Equilibration Fantastic movie with Christian bale 1 Link to comment Share on other sites More sharing options...
sweettooth Posted June 14 Share Posted June 14 dont count on the ACI probe to be accurate. I use my inkbird to set my humidity, my ACI is waaay higher, but only when lights on, tried making a little foil hat but didnt do much, i use it to control my fans and thats it. i dont too bogged down by vpd anymore, as long as its in a "zone", plants are healthy Link to comment Share on other sites More sharing options...
Military Grade Posted June 14 Share Posted June 14 My Govee was a bit higher than my AC humidity reading, not sure what one is right I wouldn't put all my faith into them or a inkbird at that Link to comment Share on other sites More sharing options...
Military Grade Posted June 14 Share Posted June 14 (edited) I still need to try that cooking foil trick on my AC probe, maybe that will bring the AC and Govee closer together Edited June 14 by Military Grade Link to comment Share on other sites More sharing options...
The Green Manalishi Posted June 14 Share Posted June 14 Boveda do a calibration kit, seal your kit in with one, and calibrate it to 75rh at 20c or find its true reading. 1 Link to comment Share on other sites More sharing options...
MindSoup Posted June 14 Share Posted June 14 You can calibrate with some wet salt and sandwich bag . 1 Link to comment Share on other sites More sharing options...
Shumroom Posted June 14 Share Posted June 14 10 hours ago, MindSoup said: Good point . If anyone can suggest a practical and accurate way to measure LSTs then I'm all ears. Practical and accurate is a bit of an oxymoron I don’t try to get my environment 100% spot on, but I do like to have a rough idea where I’m at so I know what I need to try to improve upon Atb Link to comment Share on other sites More sharing options...
Military Grade Posted June 14 Share Posted June 14 (edited) 1 hour ago, MindSoup said: You can calibrate with some wet salt and sandwich bag . I keep meaning to try that, ain't it a bottle cap filled with salt and a few drops of water just to make it moist in a sandwich bag if i remember right. I'm gonna go watch some YT videos Edited June 14 by Military Grade 1 Link to comment Share on other sites More sharing options...
MindSoup Posted June 14 Share Posted June 14 It was a while ago that I did it, but yeah basically. Her we go. 1 1 Link to comment Share on other sites More sharing options...
Military Grade Posted June 14 Share Posted June 14 (edited) Dam i don't have any distilled water at hand, Have to remember to look for some next time i go town edit: i see he used bottle water anyways, might try that tomorrow then. Edited June 14 by Military Grade Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now